If I Could Start Again
by GloriousBlackout
Summary: When the worst case scenario occurs in Siberia, Tony struggles to deal with the consequences of his actions as he comes to learn more about the Winter Soldier's past


**A/N - This idea's been annoying me for ages but I've only just gathered the motivation to write it down. I'm not sure I'm entirely happy with it, but I hope you enjoy it and, as always, any feedback is appreciated :)**

* * *

When he looks back on those fateful moments in Siberia, the most sickening thing Tony remembers is just how easy it had all been.

It had been easy to deliver a final blow to Steve's body which had left him either dazed or unconscious on the ground (in the rush of the moment, Tony hadn't bothered to check). It had been easy to turn and lean over the already broken form of Barnes; to ignore the man's pain and the shattered ruins of his left arm and replace what he was seeing with the image of the empty-eyed assassin from Hydra's footage.

It had been easy to place a metal hand directly over the man's heart and fire off one short blast. The impact hadn't been particularly powerful, courtesy of his failing suit, but it was strong enough that he could feel fractured ribs shifting under his grip, and the wide-eyed shock in Barnes' eyes suggested that the blow had been more than enough.

Tony knows, looking back now, that the entire sorry ordeal must have been over within a matter of seconds, but the details which linger in his mind seem to spread over days. He can remember with great clarity the way his own breath had caught in his throat in the quiet moments following the blast; the way the chest under his palm had shuddered fitfully in an attempt to seize what precious little oxygen it could. He can remember the painful drag of his eyes moving up to meet those of the man he'd just condemned to death, and the feeling of ice slipping into his gut as he'd seen not the cold, detached eyes of the being who'd killed his mom, but the tired, accepting eyes of someone who has suffered far too much and was facing the end.

The murderous rage had fled him then, despite the knowledge that it was too late, and when Barnes' remaining hand had weakly rested on top of the metal of Tony's suit, he hadn't had the energy to push it away. He'd stayed for the remainder of the time it had taken for those weary eyes to close and the chest beneath his hand to still, and all the while his own heart had roared in his ears to the point where he thought it might leap out of his chest.

The moments after are a rush that, even months later, Tony can barely recall. All he knows is that he'd fled, knowing all too well that if he was still there when Cap woke up he'd likely never leave the compound alive, and limped towards the quinjet the pair had stolen from Leipzig. He thinks he may have met T'Challa on the way – remembers a numb acceptance that _of course_ the king had followed them here – and muttered something about taking Steve somewhere safe, before leaving the man behind to fly away.

The entire journey from Siberia to New York is a blank. Tony imagines that is probably for the best.

* * *

The aftermath of the media-dubbed "Civil War" is as chaotic as one would expect, although mercifully Tony has very little to do with it. Perhaps it would have been better if he'd been given the chance to admit to their mistakes at one press conference after another, but one meeting with General Ross had been enough to inform him that the man had no intention of letting anyone but himself take charge of the sorry mess they'd made.

Instead, Tony holes himself up in the Avengers Tower and tries to ignore how oppressively quiet it is now. He fends off sleep by working tirelessly in the lab or beating the shit out of punching bags in the gym, and occasionally he'll steel himself and switch on the news.

The media seem to be thoroughly enjoying themselves in their dissections of that eventful week. It seems that support for the Accords is now at an all-time high, although Tony doubts there are many Avengers left for them to apply to, and although the compound in Siberia was investigated, any trace of Cap and the Winter Soldier was long gone by then. Coincidentally (in the eyes of the press anyway), King T'Challa had retreated to Wakanda to carry out his duties, but not before dropping off a certain Helmut Zemo in Berlin.

These are the facts, but each news channel is also filled to the brim with people who have no idea what they're talking about theorising about things they don't understand, and there's always only so much that Tony can stand to watch before he shuts off the TV.

More than once he loses all restraint and simply resorts to throwing the remote at a wall.

* * *

"You're not going to change what happened by working yourself to death, you know."

It's not the first time Rhodey's tried to make him see sense and it won't be the last, but Tony simply shrugs and turns his attention back to encouraging his friend to take another step. The combined weight of Rhodey and the prototype he's built to aid his recovery is almost too much, but the pain gives Tony something to focus on that isn't the memory of fading blue eyes, so he deals with it. Together they manage to clear ten feet before Rhodey collapses breathlessly to the ground, and while it's not as far as he'd like, Tony finds comfort in the fact that his work is yielding progress.

When they've both caught their breath, Tony turns his attention to the prototype attached to Rhodey's legs and extending to the level of damage at his spine, and already he can feel his mind processing all the improvements he still needs to test.

"How does it feel? Is it too heavy? Because if it's too heavy I can make some alterations. It should only take a week to test them out, but I can shorten that if I…"

He's stopped by the firm grip of Rhodey's hand on his shoulder, and that's all it takes for his mind to quieten. He takes a shuddering breath and closes his eyes, and it hits him that he's so _so_ tired, but as much as he'd like to drift into sleep with the comforting presence of Rhodey beside him, he knows he doesn't have that right. There's still too much work to be done, and he knows who will be haunting him in his dreams if he lets himself sleep.

"It's fine Tony," Rhodey says, his tone calm as if he's consoling a child. It occurs to Tony that he's not usually this sober when he hears his friend talk to him in this way. "I mean, I'm not going to be running a marathon anytime soon, but the fact that I can even stand is a miracle at this point."

Tony nods and opens his eyes to face his friend. He gives him what is likely an unconvincing smile, before looking away and becoming abnormally fixated on a small stain on the floor. In spite of Rhodey's words, he knows that he can't stop working now. He needs to keep working until Rhodey can run for miles without tiring; until he can fly again, if that's something he'll one day want to do. It's the only way he knows he'll ever be able to start forgiving himself for everything that's happened.

"Hey," Rhodey says, dragging Tony back to the present. "Why don't we call it a day and you go get some rest? I know it sounds like a shit idea now, but trust me, you'll feel better for it."

As much as Tony doubts that, he finds that he can't refuse. He groans as he drags himself to his feet, and helps Rhodey get up as well before guiding him towards his wheelchair. They're both breathless again by the time Rhodey's sat down, and it takes longer than usual for Tony to remove the prototype (not helped by his friend's absolute insistence that he'll do no more work on it today), but eventually he's free and Tony leaves Rhodes with the promise that he will at least try to get some sleep.

And try he does, as he stumbles into his room barely an hour later and lets himself collapse with exhaustion onto the bed. It's a futile venture, considering he knows that what little sleep he gets will be restless, but he supposes that he might as well follow Rhodey's advice and try to look after himself.

It takes waking up covered in sweat, with a scream caught in his throat and the lingering images of the broken bodies of his parents and Barnes stuck in his head, to remind him that not sleeping is probably the better idea after all.

* * *

It takes a lot of digging, but eventually Tony uncovers Hydra's files from the Winter Solider project. Many of them are encrypted, but it's nothing that FRIDAY can't work out, and though he knows that Rhodey, or even Pepper if she could see him now, would disapprove, he knows that he needs to face this. He needs to know who exactly he murdered in cold blood.

The details of what happened to James Buchanan Barnes in the aftermath of the war turn out to be more sickening than Tony had previously been able to comprehend. He reads endless notes about how they'd started work on the prosthetic arm while Bucky was still conscious, how they would force him into the ice between missions and wipe his mind at the mere suggestion that he was becoming more human than machine.

The way the notes are presented resemble a report Tony himself may write on one of his inventions. There's a certain pride in the efficiency of the weapon the scientists have created, with no dwelling on the human life they've destroyed as a result. Mission reports are presented in painstaking detail and Tony feels his heart sink at the mentions of the punishments Bucky would receive if he demonstrated even the slightest uncertainty or remorse.

It all leads to a confirmation of what he thinks he's known all along; that when he'd let rage guide his actions in Siberia, he'd allowed himself to kill an innocent man.

He throws up more than once while reading the files, and has to stop to distract himself with his work on multiple occasions. His prototype for Rhodey's walking aid is coming along nicely due to him sacrificing human needs like sleep and food in order to work for hours on end. He's spent days trying to improve the contraption and allow it to better communicate with Rhodey's brain so that the conscious command to move gets an appropriate response, and he thinks that just maybe, if this works, he could find a way to mass-produce it and provide it to disabled people all over the world. At least then maybe he'd be doing some good…

The words of Charlie Spencer's mother come back to haunt him then - how guilt and generosity are so often linked – and it hurts him more than it should to realise that he's simply moved on to yet another outlet for his guilt.

He's starting to wonder if he will ever stop fighting to redeem himself.

* * *

He's halfway through an old, black and white video of the Winter Soldier's conditioning when Rhodey lets himself into the room, relying on a wheelchair this time around. Tony's so caught up in what he's seeing that he doesn't even notice the other man's presence until he's right by his side, and when he looks at his friend he finds his own horror splayed across the other man's face.

"So this is what you do when you're refusing to answer my calls," Rhodey remarks, but any humour he may have intended falls flat as his eyes take in what's happening onscreen. Tony reluctantly pauses the footage mid-scream and tries not to dwell on the pain on the soldier's face as his memories are burned from his mind.

"I needed to-" he starts, before pausing. Honestly, he's not entirely sure what he needs. "I need to know what happened to him. I need to know who I killed."

Rhodey sighs, but mercifully doesn't immediately say anything. The silence that falls between them is a heavy one but Tony lets it soak over him, taking solace in the temporary absence of screams. He could close his eyes now and drift off into sleep, so intense is the exhaustion he's let himself fall into, but he knows that he will face night terrors if he does and he's not sure he could handle Rhodey seeing him like that.

He jumps when Rhodey speaks again. "So how long is this going to continue? How long are you going to keep punishing yourself?"

Tony can practically feel his friend's gaze piercing into his soul and he shudders. It hits him then that he's gone a long time with very little human interaction; he hadn't realised he'd isolated himself to such an extent that even a conversation with his best friend feels alien.

"As long as it takes," he says finally, and he knows the answer isn't one that will reassure Rhodes. It's the only answer he has though; he hasn't really given much thought to how long this will last. He turns to Rhodey and tries to smile, but he knows it must come out as a grimace.

Tony doesn't know how much time passes before he finds the nerve to speak up again. "I'm going to ask you something, and I need you to be honest with me." He looks at Rhodey and sees the other man nod in response. "If you'd been there with me, back in Siberia, what would you have done?"

Tony can see the temptation to lie flash across Rhodes' face for the briefest of moments, before the other man takes a deep breath and turns away, facing the frozen image plastered on the screen. "You know what I would have done, Tony," he says finally, regretfully. Tony looks at his friend, really looks at him, and sees that he too is exhausted and likely only barely coping with everything that's happened. Guilt hits him at the fact that it's taken him this long to notice. "I would have done everything I could to stop you from doing something you'd regret."

The words carve a deeper hole into Tony's chest, but true enough, they serve as confirmation of what he suspects he already knew. Had Rhodey not been injured it is likely that Tony would have asked him for help, and maybe that would have been enough to fix everything. "Thanks," he says, because in spite of the pain of Rhodey's words, he knows he needed the honesty.

"Look, I know I can't stop you from watching this stuff," Rhodey says resignedly, gesturing towards the tapes surrounding the TV screen. "I wish I could but…" _But I know you too well_ is what remains unsaid, and the words dance around Tony's brain like an accusation. "All I'm saying is, if you're going to subject yourself to this stuff then I'd rather you didn't do it alone."

Tony doesn't particularly want Rhodey to leave with those images in his head, but he knows that any attempt to get him to leave is going to be met with resistance and he doesn't have the energy to deal with that right now. So instead, he simply moves closer to Rhodes, subconsciously seeking human contact after weeks of denying himself, before resuming the video and preparing for its contents to chip away at his soul.

By the time the footage cuts out, he's left feeling numb and a sideways glance shows him that Rhodey's face is ashen, and a long time passes before either has the energy to cut off the hissing static.

* * *

He stumbles across the worst of the footage on an otherwise quiet Sunday afternoon.

It's a silent video showing Steve and Bucky before any of the horrors of their futures had marred them, and the most painful thing about it is just how happy they seem. Bucky laughs without abandon while Steve grins at him, perhaps glad that a private joke has had the desired effect, and they're both so fucking _young_ that Tony feels like someone has torn into his heart.

It occurs to him that he has never seen Steve smile like that. Oh, he's seen him smile with relief in the aftermath of battles and seen him laugh in their lighter moments, when they could still call themselves a team.

Tony has never seen him smile so much that it must hurt, however; has never seen his eyes crinkle up with laughter and look at the person next to him as if they held the beauty of the sun.

The worst thing of all is that Tony knows that Steve will never smile like that again. And it's all his fault.

* * *

It only takes a year for the world to fall into madness again as an ancient cosmic being calling himself Thanos brings down endless hordes of armies upon them. It's only the third time that the Avengers have been called to action since the introduction of the Sokovia Accords, but funnily enough the governments of the world are a lot more willing to let them fight when faced with imposing purple-faced monsters.

Tony welcomes the fight, if only because it gives him a purpose again, and he lets himself become mindless as he takes down the faceless alien hordes that descend from the skies. Vision and Spiderman are fighting nearby, and Rhodey is flying alongside him in a modified suit, his voice the only thing cutting through the noise that surrounds them, and Tony clings to it in his refusal to let anything hurt his best friend again.

A sudden wooping in his ear is his first hint that they are no longer alone in this fight, and he feels his heart soar as he scans his surroundings and sees the familiar forms of Wanda, T'Challa, Sam and Nat join the fray. When he concentrates on Rhodey and Peter's running commentary (the latter being especially excitable) he realises that more of their old allies have joined them, and for the briefest of moments everything feels normal.

He spends what time he can spare between firing at their enemy checking up on his team-mates and smiling in spite of the direness of their situation, only for the world to go quiet and his heart to stop when his eyes finally land on Steve.

The man looks much the same as he did before; all red, white and blue with the shield never far from his grasp. There's a certain ferocity in his movements that Tony doesn't think was there before - in the way he tears through the army as easily as paper - and though he cannot see the man's face he imagines there must be a darkness there that he'd only previously seen in Siberia.

Miraculously, after days of fighting and likely countless casualties, they win. Tony spends the immediate aftermath of the battle wandering aimlessly through the rubble, keeping alert for any sign of wounded civilians who may not have been able to evacuate in time. Around him, he can see others doing the same; Rhodey leads a small squadron of soldiers as they rummage through the remains of buildings and Natasha is leading a young girl away from the carnage towards the established safe zone in the city's outskirts. It doesn't take long for him to stumble upon Steve, flanked by Sam and Wanda, and a heavy weight doesn't have time to settle in his chest before the man turns and meets Tony's gaze.

With his helmet removed, Tony can see that Steve looks as tired as he feels. Dark circles line his eyes and there's a steeliness in his expression that Tony barely recognises. He half expects guilt to swallow him whole once more, but instead he simply feels numb and tired and resigned to the fact that Steve has every right to hate him.

The other man doesn't seem angry though. From this distance, it is possible that Tony could be wrong, but the weariness he sees doesn't seem to be marred by hate. Perhaps too much time has passed for that and they've both been forced to accept that they're never truly going to be okay again, and the realisation hurts so much that Tony thinks he would prefer a punch in the face to the tired solemnity Steve gives him instead.

It's only now that he becomes aware that Sam's trying to guide Steve away, and it seems to take a few seconds for Steve to relent. Before he turns though, he gives Tony a single, curt nod and Tony returns it.

He wonders if he will ever get the opportunity to apologise to Steve directly, but for now he supposes this brief exchange will have to be enough.

* * *

A parcel arrives at the Avengers base two weeks later, containing a new phone and a note: _"In case you need us – Steve."_

It's a bitter reminder that Steve is a better man than Tony deserves, but he keeps the phone by his side in the hopes that one day he will be worthy of using it.

* * *

It's a peaceful morning when he arrives at Arlington Cemetery.

The sun warms his face while a light breeze prevents the heat from becoming unbearable, and Tony keeps his head down out of respect to the fallen who surround him, occasionally nodding at the silent family members who pass by. He does not expect to be here long, nor does he think he has the right to linger among those who have sacrificed so much, so he makes his way directly towards the empty grave he's searching for.

He knows that this is not truly Barnes' resting place. The grave has been here since he was assumed dead in 1944; a place for his family to grieve a son whose body they'd never receive. In reality, he likely rests in Wakanda, with green trees and mountains surrounding him, but Tony knows he is not worthy of paying his respects there. An empty grave will have to do.

As he stands before the white stone, with the wrong date engraved on its surface, he finds that any words he'd had prepared refuse to come forth, as if something is physically constricting his throat and rendering him silent. There is little he can say that will make a difference, and he knows his conscience will be no lighter for having come here, and for several long seconds he thinks that perhaps he shouldn't have come at all.

However, he is here now, and he knows he can either admit defeat and walk away or say what needs to be said.

"I'm sorry," he says eventually, the words sounding woefully insufficient when said aloud. "I should have thought, I didn't think…" And there had been the fatal flaw. A life ended and Zemo's plan was fulfilled because for only a few moments, he'd refused to think.

He finds himself walking towards the stone, his eyes scanning the carved dates - _he was only 28 when they turned him into a weapon_ \- and lays his hand gently on the surface. The stone is cool beneath his palms, and Tony forces out his next words through a lump in his throat.

"You deserved so much better, kid."

When he leaves five minutes later, he still wonders if he should have bothered to come at all.

* * *

In an ideal world, Tony holds onto his rationality when presented with the horrifying truth of his parents' murders.

In an ideal world he is stopped by Steve, or comes to his senses just in time, or doesn't even receive the evidence which leads him to Siberia in the first place and lives out his life in blissful ignorance.

In an ideal world, Bucky is given the chance to survive and recover from the horrors of his past; is given the chance to fight alongside the Avengers against Thanos and all the other threats they find themselves facing.

Tony knows he is not living in an ideal world and that no amount of regret will ever erase what he's done, nor will it bring Bucky or his parents back. He knows that all he can do is dedicate his efforts to ensuring that nothing like this ever happens again; to helping clear Bucky's name to the public, and somehow redeeming himself in Steve's eyes, and continuing to fight for the people he's sworn to protect.

It's never going to be enough, but he's slowly learning to let himself believe that it's a start.


End file.
